Magnetic field lines of two magnets are shown in figures $A$ and $B$. Select the figure that represents the correct pattern of the field lines. Give reasons for your answer. Also,name the poles of the magnets facing each other.

Two coils $C_{1}$ and $C_{2}$ are wrapped around a non-conducting cylinder. Coil $C_{1}$ is connected to a battery and a key $K$,and coil $C_{2}$ is connected to a galvanometer $G$. On pressing the key $K$,current starts flowing in the coil $C_{1}$. State your observations in the galvanometer for the following cases:
$(i)$ When key $K$ is pressed on.
$(ii)$ When current in the coil $C_{1}$ is switched off.
$(iii)$ When the current is passed continuously through coil $C_{1}$.
$(iv)$ Name and state the phenomenon responsible for the above observation. Write the name of the rule that is used to determine the direction of the induced current.

If the direction of current is reversed,the direction of magnetic field is also reversed.

How does a current-carrying solenoid behave?

Meena draws magnetic field lines of a field close to the axis of a current-carrying circular loop. As she moves away from the centre of the circular loop,she observes that the lines keep on diverging. How will you explain her observation?

By placing an iron-like metal inside the solenoid,its magnetic field becomes $......$